Organic materials commonly referred to as photoresists are recording media on which information can be recorded in the form of a relief pattern. Such media, when exposed to a light pattern, change their solubility characteristics in those areas struck by the light. Photresists may be developed by contacting them after exposure with a solvent which dissolves the more soluble portions, leaving the less soluble portions in a relief pattern which corresponds to the information contained in the light pattern. Negative photoresists are initially soluble in the developer solution and the exposed portions become insolubilized. Positive photoresists are initially insoluble and become soluble in the exposed portions.
Recently, suitably modulated electron beams have also be utilized for recording relief patterns. Electron beams, by virtue of their shorter effective wavelengths and greater depth of focus, can thus record information at higher resolution or density than can light beams. This ability would be highly useful in the fabrication of integrated circuitry having very small circuit elements employing processes using conventional photoresist techniques. These processes employ layers of positive electron beam sensitive materials wherein the thickness of the layer is equal to or less than the penetration depth of the electron beams. As a result of exposure and development, the exposed regions of the electron beam sensitive material are removed to expose the substrate. Positive electron beam sensitive materials are also useful in serial information recording whereby individual "signal elements" are formed as minute, well-definited depressions in the surface of the electron beam sensitive material, which do not necessarily extend through the layer, thus making possible the use of layer thicknesses which exceed the penetration depth of the electron beam.
Materials presently known which can be employed as positive electron beam recording media include certain commercially available photoresists, and organic polymers such as polymethyl methacrylate which are not considered to be photosensitive. These materials, due to their relatively low sensitivity to electron beams, require electron beam sweep rates for recording which are considerably slower than rates obtainable with the use of presently available equipment. Further, some commercially available photoresists which are electron beam sensitive are mixtures of organic materials which have compositions that can vary sufficiently from batch to batch such that recording media prepared therefrom show marked non-reproducibility of important relief-forming properties. Thus, improved materials which have a high electron beam sensitivity, are capable of providing well resolved relief patterns and can be formulated reproducibly would be highly desirable.